Lepidium meyenii (Maca) enhances the serum levels of luteinising hormone in female rats

Ethnopharmacological relevance: Lepidium meyenii (Maca) is traditionally employed in the Andean region for its supposed fertility benefits. This study investigated the effect of Maca on the serum pituitary hormone levels during the pro-oestrus phase. Materials and methods: Maca powder was made from the tubers of Lepidium meyenii Walp collected, dried, and reduced to powder at the plantation in Junin Plateau and was purchased from Yamano del Peril SAC. The Maca powder was identified by chemical profiling and taxonomic methods. Two groups of female Sprague-Dawley rats were provided feed with normal feed containing 5%, 25%, or 50% Maca powder ad libitum for 7 weeks. At 1800 h of the proestrus stage, the rats were euthanised, and blood samples were collected for serum isolation. The serum pituitary hormone levels were measured using enzyme-linked immunosorbent assays (ELISAs). Results: No significant differences in feed intake or growth rate were observed among the rats. During the pro-oestrus stage, a 4.5-fold increase (P<0.01) in luteinising hormone (LH) and a 19-fold increase (P<0.01) in follicle-stimulating hormone (FSH) were observed in the sera of rats fed with 50% Maca powder compared with the control rats. No significant differences were observed in the levels of the other pituitary hormones, including growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), and thyroid-stimulating hormone (TSH). A dose-dependent increase of LH serum levels was observed within the range of 3-30 g Maca/kg. Furthermore, the enhancement of the LH serum levels was specific to the pro-oestrus LH surge. Conclusions: The present study demonstrates that Maca uniquely enhances the LH serum levels of pituitary hormones in female rats during the pro-oestrus LH surge and acts in a pharmacological, dose-dependent manner. These findings support the traditional use of Maca to enhance fertility and suggest a potential molecular mechanism responsible for its effects. (C) 2013 Elsevier Ireland Ltd. All rights reserved.